Reef Central Online Community

Go Back   Reef Central Online Community > General Interest Forums > The Reef Chemistry Forum
Blogs FAQ Calendar Mark Forums Read

Notices

User Tag List

Reply
Thread Tools
Unread 04/17/2018, 07:37 AM   #1
AquaAdam
Registered Member
 
Join Date: Mar 2016
Location: Ontario
Posts: 95
Question on mag dosing.

I've been watching my parameters and my magnesium seems to drop 15-20ppm per day. I currently use red sea's abc foundation to dose but they say the max daily increase is only 10ppm for magnesium. So, just wondering what my options are since, in order to stabilize my tank on a daily basis, I would be adding more than the recommended dosage.

Thanks!


AquaAdam is offline   Reply With Quote
Unread 04/17/2018, 08:13 AM   #2
mcgyvr
Registered Member
 
mcgyvr's Avatar
 
Join Date: Sep 2003
Location: North Carolina
Posts: 20,050
Yes.. as stated its rather confusing..
OBVIOUSLY if your parameters are swinging more than that daily you need to dose more than that..

Its really saying don't let your mag swing/change by more than 10ppm per day..
Just like don't let your alk swing by more than 1dkh per day..
Its really their "recommended" maximum daily change and when it exceeds that you should start dosing.. So because you are losing 15-20ppm a day you should have already been dosing before you got to 10ppm drop..

You are dosing to prevent that swing/change from happening in the future..

If you want to stick with their recommendation then you can start by dosing 10ppm today and tomorrow your swing is only 5-10ppm and then you can add on the extra 10ppm so that you aren't swinging by more than 10 at one time..
Going forward you are replenishing what is being removed so your net swing is zero even though you might be dosing 20ppm the real daily increase is a net zero..


__________________
Who me?
mcgyvr is offline   Reply With Quote
Unread 04/17/2018, 11:44 AM   #3
hkgar
Registered Member
 
hkgar's Avatar
 
Join Date: Oct 2002
Location: Dewitt MI
Posts: 5,051
A drop of 15-20 for Mag seems rather excessive. My mag doesn't move that much in a week or more.

How large is the tank? What are your levels for Alk and calcium? How much are they changing daily.


__________________
Gary


180 gallon, 40 gallon sump, 3 250 W MH + 4 80W ATI T5's, MTC MVX 36 Skimmer, Apex controller Aquamaxx T-3 CaRx

Current Tank Info: A 2 Barred Rabbitfish, Red Head Salon, Yellow/Purple, McMaster Fairy, Possum, 2 Leopard Wrasses, Kole, & Atlantic Blue Tangs, 2 Percula Clown, 3 PJ and 1 Banggai Cardinalfish , Swallowtail, Bellus and Coral Beauty Angels
hkgar is offline   Reply With Quote
Unread 04/17/2018, 01:47 PM   #4
hbrochs
Registered Member
 
hbrochs's Avatar
 
Join Date: Oct 2014
Location: Westchester, NY
Posts: 439
I never have to dose Mg and my tank has a bunch of SPS and LPS. I dose Alk and Ca, and the Magnesium stays in range with just regular water changes. Is there a chance this is just testing error? Mg typically has to be brought up when you first set up the tank, but after that I think its unlikely that its truly dropping that fast. There is some inherent bias when we test. You have an expectation that you are trying to verify with the test, and that can color your reading of the result. You could take a sample to the local fish store and get a base line, and then bring them another sample in three or four weeks and compare.


__________________
80 Gallon Innovative Marine long shallow reef
30 Gallon tank for raising baby clownfish

Current Tank Info: Innovative Marine SR-80
hbrochs is offline   Reply With Quote
Unread 04/17/2018, 03:24 PM   #5
Phixman
Registered Member
 
Join Date: Jan 2017
Location: Lynnwood, WA
Posts: 176
How many days consecutively have you tested? It could be just the margin of error.


Phixman is offline   Reply With Quote
Unread 04/17/2018, 04:24 PM   #6
Phixman
Registered Member
 
Join Date: Jan 2017
Location: Lynnwood, WA
Posts: 176
Here is mine for comparison, mine always drops during a water change, so I just do 25%, and another 25% the next day so I don't get big swings, I dose 30ish ml of Mag to keep Mag in check during the first water change to prevent swings as well. As you can see from the image my mag has been stable all week, the last test looks to be a drop, but it's just the ME.




Phixman is offline   Reply With Quote
Unread 04/17/2018, 10:36 PM   #7
bertoni
RC Mod
 
Join Date: Mar 2002
Location: Mountain View, CA, USA
Posts: 88,616
I agree that 10-15 ppm per day seems like a huge amount of magnesium consumption. What are the calcium and alkalinity consumption rates.


__________________
Jonathan Bertoni
bertoni is offline   Reply With Quote
Unread 04/18/2018, 06:41 AM   #8
AquaAdam
Registered Member
 
Join Date: Mar 2016
Location: Ontario
Posts: 95
Hello and thank-you for the replies.

mcgyver - Thanks for clarifying that for me. That's what my ultimate goal is - replenishing what is being removed so your net swing is zero even though you might be dosing 20ppm the real daily increase is a net zero..


hkgar - Tank is a 60 cube with 15gal sump - Other levels are usually good. my calcium doesn't drop too much - I didnt have time to check the levels yesterday but I will tonight - and my Alk stays pretty stable. Yesterday it was 8 but I try to keep it at 8.3-8.4.

hbrochs- I don't think it is a testing error. My mag has always dropped rather quickly. I believe it might be due to the live rock I have inside the tank. Whatever kind it is, it seems to eat it up. I do have coral as well but not too much just a couple frogspawn, birdsnest, zoas, and some shrooms at the moment. I'm going to take your advice on having someone else check the levels and take it to a lfs near me one day this week just to verify test results.

Phixman - I didn't know you could monitor Mag on the apex. I don't have one but I definitely want one, as it would be alot easier to visually see the drop on a graph than through test kits. Now all I need is a couple thousand.....


AquaAdam is offline   Reply With Quote
Unread 04/18/2018, 09:32 AM   #9
hkgar
Registered Member
 
hkgar's Avatar
 
Join Date: Oct 2002
Location: Dewitt MI
Posts: 5,051
Quote:
Originally Posted by AquaAdam View Post

Phixman - I didn't know you could monitor Mag on the apex. I don't have one but I definitely want one, as it would be alot easier to visually see the drop on a graph than through test kits. Now all I need is a couple thousand.....
Apex does not monitor Mag. The graph is created by posting the results from your testing.


__________________
Gary


180 gallon, 40 gallon sump, 3 250 W MH + 4 80W ATI T5's, MTC MVX 36 Skimmer, Apex controller Aquamaxx T-3 CaRx

Current Tank Info: A 2 Barred Rabbitfish, Red Head Salon, Yellow/Purple, McMaster Fairy, Possum, 2 Leopard Wrasses, Kole, & Atlantic Blue Tangs, 2 Percula Clown, 3 PJ and 1 Banggai Cardinalfish , Swallowtail, Bellus and Coral Beauty Angels
hkgar is offline   Reply With Quote
Unread 04/18/2018, 10:37 AM   #10
Tripod1404
Registered Member
 
Join Date: Mar 2016
Posts: 1,821
Wow that is very unusual. Biologic consumption of Mg is mainly by coraline algae and even they only have about 4.4-4.5% skeletal weight by Mg.

So the expected Mg consumption of coralline with respect to alk is around 4.4 ppm magnesium for each 2.7 dKH of alkalinity, or 1.6 ppm for each 1 dKH. So a swing of 10-15ppm Mg needs an alk consumption of 7-10 dKH per day.

I think you either have a bad test that gives wildly inconsistent numbers or there is an abiotic reaction going on.


Tripod1404 is offline   Reply With Quote
Unread 04/18/2018, 09:45 PM   #11
AquaAdam
Registered Member
 
Join Date: Mar 2016
Location: Ontario
Posts: 95
Apex does not monitor Mag. The graph is created by posting the results from your testing. - So thats through their app, and you just type in your numbers?

Tripod1404 - I'm fairly certain I purchased a new test kit a while back as I was wondering the same thing then, but got the same results. I'm going to take my water in to have someone else test it and compare. what is an Abiotic reaction?


AquaAdam is offline   Reply With Quote
Unread 04/19/2018, 09:54 AM   #12
Tripod1404
Registered Member
 
Join Date: Mar 2016
Posts: 1,821
@AquaAdam , abiotic means there is a non-biological process that consumes Mg.


Tripod1404 is offline   Reply With Quote
Unread 04/19/2018, 10:39 AM   #13
AquaAdam
Registered Member
 
Join Date: Mar 2016
Location: Ontario
Posts: 95
So here are my test results today. I'm going to be taking my water to get tested but just wanted to post them. I'll update once I have the other results.

Salinity 1.024
Mg - 1230 - I let it go for a couple days to try to calculate loss/day according to red sea
Ca - 464 - no issues here really
dkh - 8.1 - I dosed 3 days ago so this tells me I'm loosing .1ppm/day

I'm using a salifert test kit for the mg thats good until end of 2019, so I don't think it's the kit.


AquaAdam is offline   Reply With Quote
Unread 04/19/2018, 11:16 AM   #14
Sk8r
RC Mod
 
Sk8r's Avatar
 
Join Date: Feb 2006
Location: Spokane WA
Posts: 34,628
Blog Entries: 55
What puzzles me is a drop in alk while the mg is testing over 1200. Do you have some Salifert test kits you can use to doublecheck that alk and cal as well as mg? I'm wondering if those tests are accurate. If your alk is down, that could answer for some screwiness. Also that cal is quite high. If alk and cal get screwed up, it can deposit in your pipes and hoses and such.


__________________
Sk8r

Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low.

Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.
Sk8r is offline   Reply With Quote
Unread 04/19/2018, 10:05 PM   #15
bertoni
RC Mod
 
Join Date: Mar 2002
Location: Mountain View, CA, USA
Posts: 88,616
If the magnesium is forming magnesium carbonate somehow, that'd explain the drop in both levels. We'd need a chart of measurements for the three parameters and dosing quantities to say much, though.


__________________
Jonathan Bertoni
bertoni is offline   Reply With Quote
Unread 04/20/2018, 09:37 AM   #16
AquaAdam
Registered Member
 
Join Date: Mar 2016
Location: Ontario
Posts: 95
So in store they tested for mg and it came in at 1200; so even lower than my test kit. (Both were salifert) I bought another salifert mg test kit yesterday so I am going to test with the brand new one today, as well as the old and compare results. From what I understand the majority of people are using salifert test kits to test for mg. Is there a better test kit out there, thats reasonably priced? I dont think hanna makes one..


AquaAdam is offline   Reply With Quote
Unread 04/20/2018, 09:49 AM   #17
bertoni
RC Mod
 
Join Date: Mar 2002
Location: Mountain View, CA, USA
Posts: 88,616
The Salifert kit has been fine, in my experience, but any kit can fail. I'm not sure what's happening here, but a few days of measurement might give us a good trend line. If you could test at the same time for a bit, that might help a bit, but the results in theory should be stable.


__________________
Jonathan Bertoni
bertoni is offline   Reply With Quote
Reply

Tags
dosing, magnesium, red sea

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



All times are GMT -6. The time now is 03:50 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Use of this web site is subject to the terms and conditions described in the user agreement.
Reef CentralTM Reef Central, LLC. Copyright ©1999-2022
User Alert System provided by Advanced User Tagging v3.3.0 (Pro) - vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.